1. Field of the Invention
The present invention relates to a portable hand-held power tool, especially in the form of a drilling or chisel hammer and including a drive assembly for driving a tool spindle along an operational axis, which comprises a drive assembly in the form of an electric motor and a movement converter in the form of a percussion mechanism, if necessary in combination with a transmission. The drive assembly is located in the tool housing. Further, the hand-held power tool includes a first handle pivotable by a first handle suspension around a first pivotal axis, and a second handle pivotable around a second pivotal axis by a second handle suspension. Both handles extend from the opposite sides of the housing and are respectively held in their initial position by spring means.
2. Description of the Prior Art
Hand-held power tools of the type discussed above generate strong vibrations during operation along the operational axis in the housing. As a result of the spring-loaded handle suspensions, these vibrations are transmitted at considerably reduced intensity to the handles.
From U.S. Pat. No. 4,576,241, a pneumatic chisel and drilling hammer is known in which two handles project from opposite sides of the housing. Both handles are provided at the free ends of levers, pivotally supported at the head of the housing. Furthermore, between the levers and the housing, respective helical springs are provided, which extend parallel to the operational axis, which insulate the corresponding handles from the head of the housing against vibrations acting in the direction of the operational axis.
In this case, the head and the handle assembly are formed as an assembly unit, in order to enable their retrofitting at the existing chisel or drilling hammer.
This type of handle assembly, however, has the disadvantage that the constructional length of the disclosed tool increases considerably at the end remote from the working tool. In particular, with electropneumatic hand-held power tool, which, in addition to a percussion device and, possibly, an additional transmission, also includes a drive motor in the housing, the increased constructional length at the remote end of the housing would result in a very inconvenient form of a hand-held power tool that would not allow comfortable handling.